Allergic Rhinitis in Singapore – What causes it?

Allergic Rhinitis

Also known as hay fever or pollinosis, Allergic rhinitis is a type of inflammation in the nose which occurs when the immune system overreacts to allergens in the air. These allergic symptoms are triggered easily by things like house dust, can be very uncomfortable, hard to endure, disruptive to daily life and can have negative effects on your quality of sleep.

Allergic rhinitis is the most common type of rhinitis in the world, affecting almost 10-30% of the people in the world annually. It is also colloquially known as “hay fever”. This came about due to an early misconception during the 1800s that the symptoms of allergic rhinitis was brought about “by the smell of hay in the morning”, hence the term, “hay fever”.

Allergic rhinitis is a very common condition of the nose. When most patients say they have “sinus” issues, they usually are referring to allergic rhinitis. Symptoms of allergic rhinitis include an itchy nose, stuffy nose, red or watery eyes, sneezing and swelling around the eye area.  

It is very common in Singapore due to the high humidity and it is believed that 20% of the population may have this condition. The incidence of these symptoms is higher in the pediatric population. 

Frequently, the patient is extra sensitive to airborne allergens. These allergens include miniscule things like house dust mites, molds, cat’s or dog’s dander or grass. Exposure to these allergens will trigger an allergic reaction which will cause allergy symptoms. This can trigger a reaction within the nose resulting in blocked nose, runny nose and sneezing.  Fluid from the nose is often clear, unlike bacterial infections where the phlegm and nasal fluid is often coloured.

This affects your nasal passage and it is uncommonly related to food allergens. Allergic rhinitis has also been said to occur seasonally. This is known as seasonal allergic rhinitis. Symptoms are the same as seasonal rhinitis and is commonly thought to be triggered by the pollen season commencing.

The treatment includes nasal sprays and antihistamine tablets. For severe allergic rhinitis, an allergy test such as a skin prick test can be performed to see what the potential triggers are. Allergen avoidance is key to treatment of allergic rhinitis. For recalcitrant problematic cases of allergic rhinitis, nasal surgeries can be performed to improve nasal airflow.

Allergy testing is a way to determine what specific allergens a patient is susceptible to. The most common way to do testing for allergic rhinitis is a skin prick test.

A skin prick test, otherwise known as a scratch test, is a method doctors use to test for any form of immediate or delayed reaction to various allergens. Allergens that are commonly tested for in the case of allergic rhinitis include:

  • dog dander
  • cat dander
  • grass bollen
  • birch pollen
  • daisy pollen
  • feathers
  • dust mites

Firstly, a suitable site for the test is to be administered has to be picked. For most patients, this is usually on the back or on the forearm. The doctor may also choose to use a patch test, which is similar. The allergens that are being tested for are usually indicated on the patient’s forearm using a black marker. 

I will then carefully administer a certain amount of the allergen onto their respective markers. I will use a special lancet to insert the examples of the allergen into the skin. This may or may not trigger an allergic reaction which will then be measured and analyzed. I will then observe the results to decide whether or not you are susceptible to getting an allergic reaction from that allergen.

This is a painless test (feels like an ant bite). It is highly accurate and safe and there are no adverse side effects associated with a skin prick test. 

The tool used only goes through the skin a tiny bit, so you will not feel much pain during the test. There will be no bleeding and the experience is much more similar to an insect bite than anything else. Most patients will tolerate it well.

This is a painless test with high accuracy and results are obtained in 30 minutes.

Skin Prick Test

Picture of a patient’s forearm after a skin prick test. The size of the bump is measured and the offending allergen is known.

There are several ways to reduce exposure to known allergens. It can sometimes be difficult to completely avoid the allergen. However, if you can reduce the amount of allergen exposure it can help. Vacuuming your room every time you have allergic symptoms is a good start.  The less you are exposed to common allergic triggers like dust mites, pollen, or animal dander, it is likely that symptoms that were once severe will become milder or disappear completely.

The first step is allergen avoidance. After an allergy test is done and allergens such as dust mites are avoided, nasal sprays can be given to help in the short term. A saline spray is done to clean the nose of allergens that could have lodged in the nose and sinus cavities. A medicated nasal steroid spray is then used to help reduce inflammation in the nose. The nasal steroid spray has very minimal absorption in the systemic bloodstream and is very safe to use in the short term period.

Antihistamine tablets can be used as adjunctive treatment to help alleviate allergy symptoms such as nasal congestion, runny nose and sneezing. Washing your face with hot water and regularly blowing your nose if you have a runny nose can also provide some temporary relief for symptoms.

Immunotherapy, otherwise known as allergy shots, are also a long term treatment for allergic rhinitis. Allergy shots are regular injections over 3-5 years in order to send little bits of allergens into your system so that your body’s immune system becomes more resistant to them.


Based on the skin prick test results, immunotherapy can sometimes be prescribed for patients who do not respond well to nasal sprays and tablets. Immunotherapy, otherwise known as allergy shots, are also a long term treatment for allergic rhinitis. Allergy shots are regular injections over 3-5 years in order to send little bits of allergens into your system so that your body’s immune system becomes more resistant to them, making you less susceptible to allergic symptoms.

Nowadays, immunotherapy in the form of injections are rare as it is more common to prescribe sublingual tablets for ease of administration. However, it is important to note that immunotherapy is a 3-year course of medication so long-term commitment is important for a good outcome.

For patients who are very troubled by nasal congestion and other symptoms despite treatment with all the above, a simple procedure to reduce the size of the inferior turbinates (radiofrequency) can be performed. The inferior turbinate is a structure that is commonly enlarged during allergic rhinitis. This can be performed under local anaesthesia in the clinic. The downtime is not severe and patients can usually return straight to work after.

Allergic Rhinitis

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